Optical waveguides, which are used for optically connecting optical devices to each other, are being developed because optical communication systems have come to be practically used as a result of the development of optical fibers.
It has been proposed to produce such an optical waveguide by a process in which a liquid photosensitive resin such as, e.g., an epoxy oligomer or acrylic oligomer is applied onto a lower cladding layer and the resultant coating is exposed to a light through a mask and then developed with a solvent to thereby form a core layer having a predetermined pattern (see, for example, patent document 1).
Patent Document 1: JP 10-268152 A
However, the process described in patent document 1 has limitations in improving suitability for mass production and attaining a cost reduction based on the suitability for mass production, because the optical waveguides in the process are produced on a silicon substrate by a sheet-by-sheet method (batch method).
Furthermore, the use of a liquid photosensitive resin has drawbacks that fouling of a photomask may occur in handling the liquid resin and that due to the flowability of the liquid, optical waveguides cannot be stably formed in terms of shape.